Method of spinning



c. w. PALMER METHOD SPINNING Filed Oct. 29. 1930 INVENTOR CHARLES W- PALMER I 3 1: #Mm

ATTORNEYS Patented Apr. 24, 1934 Miran STATES METHOD OF SPINNING Charles W. Palmer, Montreal, Quebec, Canada, assignor to Celanese Corporation of America, a corporation of Delaware Application October 29, 1930, Serial No. 491,912

6 Claims.

This inveniton relates to the preparation of artificial filaments, yarns and other textile materials and relates more particularly to the method of and means for producing colored or pigmented yarn in a commercially feasible manner.

An object of my invention is to provide method of and means for preparing artificial filaments or yarns having any desired pigment therein whereby filaments or yarns of a variety of colors 10 may be produced in small units. Further objects of my invention will appear from the following detailed description.

Artificial yarns and filaments have been dyed with organic materials known as dyes. These dyestuffs vary in light-fastness but even those dyes which are almost light-fast fade when exposed to sunlight for a prolonged period. This relative lack of permanence of color is a Very serious matter in the case of drapery fabrics that are exposed to sunlight. It would he, therefore, desirable to incorporate finely divided colored inorganic or mineral pigments which have almost unlimited fastness to light in the artificial filaments or yarn by adding the same to the spinning dope or solution from which they are formed. However the addition of colored material to the dope or solution presents serious difiiculties in commercial operation. This is due to the fact that if a variety of differently colored yarns is to be made, it would be analmost hopeless task to keep the various colored spinning dope separate and a separate elaborate system of filters, pipe lines, pumps, etc. would be required for each color, as the cleaning of such systems thoroughly for a different colored dope is entirely too laborious and expensive to be commercially practicable.

I have found that the above difliculties may be avoided by adding the desired pigment to the spinning dope at a point near the spinning jet so that if a dope containing a different pigment is to be spun, a comparatively small amount of apparatus requires cleaning.

In accordance with my invention I prepare artificial filaments containing finely divided pigments by adding the pigments to a spinning solution at a point near the spinning jet from which it is extruded.

The filaments made in accordance with this invention may be of fine size which are associated together by twisting to form yarn, or the filaments may be heavier, such as bristles, artificial horsehair and straw. Such filaments may be made of reconstituted'cellulose by the viscose, cuprammonium, Chardonnet or other process, but this invention is of' particular importance in conneotion with filaments made of organic derivatives of cellulose such as organic esters of cellulose and cellulose others. Examples of organic esters of celiulose are cellulose acetate, cellulose formate,

cellulose propionate and cellulose butyrate, while examples of cellulose ethers are ethyl cellulose, methyl cellulose and benzyl cellulose. The filaments containing the organic derivative of cellulose may be prepared by dissolving the organic derivative of cellulose in a volatile solvent such as acetone and extruding such solutions through fine orifices into an evaporative atmosphere, as in dry spinning, or into a precipitating bath as in wet spinning.

As stated, I add a finely divided pigment to the spinning solution or dope. This pigment may be white to obtain subdued lustre and increased.

opacity. Examples of white inorganic pigments are tin oxide, tin phosphate, antimony oxide, titanium dioxide, barium sulfate, lead sulfate, cal-; cium sulfate, zinc oxide, zinc carbonate, alumi-/ num oxide, silicon dioxide, barium borate, calcium borate or silicates such as china. clay or othet clays,. talc or mica. The pigment may be of organic nature such as diacetyl benzidine, diacetyl toluidine, dibenzoyl benzidine, naphthyl urea, anthraquinone, anthracene or suitable synthetic or natural resins.

If desired suitable colored inorganic pigment may be employed to obtain the desired color or shade. For a yellow color, ochre, sienna, chrome yellow, tin bronze, etc. may be employed. For a red color, Venetian red, red lead, vermillion, etc. may be employed. For a blue color, ultramarine, Prussian blue, Milori blue, etc. may be used. For green, Guignets green, verdigris, chrome green may be employed. For brown, raw umber, burnt umber or-Vandyke brown may be used. To obtain metallic effects, finely divided or colloidal metals may be employed. For shading, that is to get darker colors, lamp black, graphite or other black pigment may be added. To obtain any other colors, the pigments may be mixed as is well understood in the paint art.

The pigment is preferably added to the dope or spinning solution containing the cellulose com pound in the form of a concentrated suspension in a liquid. The amount of pigment added will vary with a. degree of subdued lustre and the depth of color desired and the nature of the pigment employed and will generally be from 0.1 to 10% of the weight of the cellulosic material present in the'finished yarn. The pigment is preferably in very fine form, the particles having a diameter of less than 0.1 to 5 microns for increased covering power. It is of importance to have the pigment of very fine sizein order to obtain the desired depth of color without the necessity of incorporating such a large amount 1 of pigment as to deleteriously affect the strength and the other properties of the yarn. This-fine size may be obtained by grinding the inorganic colored pigment either with water, an oil, part oi the spinning solution, or the solventused in 120 the spinning solution in a ball mill or colloid mill As stated the concentrated suspension of the pigment is added to the spinning solution at a point near the spinning jets or the individual spinning cells. For convenience I prefer to add the suspension of pigment to the header that supplies a unit containing a relatively small number of spinning cells. However, the addition of the pigment at a point closer to or more remote from the spinning jet is not excluded.

In order further to illustrate this invention, reference is had to the accompanying drawing, illustrating one of the many embodiments of my invention, wherein Figure 1 is a vertical cross-section of a spinning cell and Figure 2 is a front elevation, partly in section, showing one form of means for adding the pigment to the spinning dope.

On the drawing, 1 indicates the spinning cells, there usually being a plurality of such cells, say 5 to 50, to a spinning unit. Within each spinning cell 1, there are spinning jets 2, from which the filaments 3 are extruded into the drying evaporative atmosphere of the spinning cell. The drying evaporative atmosphere comprises air which is drawn through the valve 4 at the bottom of the cell past the heated pipes 5 to the outlet pipe 6 connected to a suction device.

The spinning solution or dope is supplied to the spinning jets 2 from the header 7 by means of the pumps 8 which feed a uniform, constant and measured amount of dope to the spinning jets.

For supplying a measured amount of pigment to the spinning dope, a vessel 9 is provided for containing the concentrated suspension of the pigment. This suspension of pigment is drawn through pipe 10 by means of a pump 11 to the spinning dope pipe 12 which is supplied with the spinning dope by the pump 13 from supply pipe 14. The'pumps 11 and 13 are proportional feed pumps so that the ratio of amount of suspension of pigment and spinning dope supply is constant.

. On the drawingthese pumps are shown as gear pumps which are driven by the same chain, the amount of pigment suspension supplied by the pump 11 being considerably less than the amount of dope supplied by pump 13.

The mixture of spinning dope and pigment passes to the mixer 15 which is adapted to mix the same thoroughly to form a completely homogeneous mass, and this mixture is pumped by pump 16 to the header 7. To maintain a constant pressure of the spinning dope in the header 7 and to prevent the pumping of more dope to the spinning cells than is consumed in the spinning operationQa pressure release valve 17 and return pipe 18 are provided, so that as the pump 16 feeds more dope than is used in the spinning cells, the valve 17 opens and the excess dope is returned by the pipe 18 to the feed side of the pump 16.

1 By way of example, the operation may be as folows.

A solution consisting of one 1) part by weight of acetone-soluble cellulose acetate and three (3) parts by Weight of acetone is supplied by the pipe 14. A' suspension of finely divided pigment in a solution of cellulose acetate of the' same concentration is placed in the vessel 9. The pumps 11 and 13 are of such size and are driven at such a relative rate, that the amount of spinning solution and suspension of pigment supplied is such that the arnount of pigment added is from 0.5 to 10% of the weight of the total amount of cellulose acetate present. The spinning dope or solution containing the pigment is then passed to the mixer 15 where it is thoroughly mixed to form a homogeneous mass and then pumped by pump 16 t0- .the header 7. The pump 16 pumps more dope than is actually used in the spinning cells, and the excess is returned through the valve 17 and pipe 18. From the header 7 the pigmented spinning dope is supplied in measured and uniform amount by the pumps 8 to the spinning jets 2, and the filaments 3 formed are drawn through current of heated air in the spinning cells 1 and are then drawn oii and Wound.

It will thus be seen by this invention a large variety of colored or pigmented filaments or yarns may be made in a relatively small number of spinning units. Moreover because the pigment is supplied at a point near the spinning jets, if

it is desired to change the nature of the pigment supplied, only a relatively small amount of apparatus need be cleaned. It is thus possible to make yarn having any desired pigment upon short notice so that the necessity of stocking a large amount of various colored yarn is avoided.

It is to be understood that the foregoing description is given merely by way of illustration and that many variations may be made therein, without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. Method of forming artificial filaments or yarns containing a pigment comprising adding a pigment to the spinning solution shortly be-"f fore it reaches the spinning jet and then spinningthe same.

2. Method of forming artificial filaments or yarns containing cellulose acetate and a pigment comprising adding a pigment to the spinning solution containing cellulose acetate shortly before it reaches the spinning jet and then spinning the same.

3. Metliod of forming artificial filaments or yarns containing a pigment comprising adding a pigment to the spinning solution shortly before it reaches the spinning jet, thoroughly mixing the resulting mixture to form a homogeneous mass and then spinning the same.

4. Method of forming artificial filaments or yarns containing a finely divided pigment comprising adding a definite amount of a finely divided pigment to a spinning solution while in transit to a spinning machine and shortly before it reaches the spinning jet, thoroughly mixing the same and then spinning the spinning solution.

5. Method of forming artificial filaments or yarns containing cellulose acetate and a finely divided pigment comprising adding a definite amount of finely divided pigment to a spinning solution while in transit to a spinning machine and shortly before it reaches the spinning jet, thoroughly mixing the same and then, spinning the spinning solution. 3

6. Method of forming artificial filaments or yarns comprising causing a stream of liquid containing a finely divided pigment and a stream of spinning solution to flow together in constant ratio shortly before they reach the spinning jet, thoroughly mixing the two streams and then spinning the resulting mixture.

CHARLES W. PALMER. 

